I think Sony and MS should use twitter as an example on how to handle screen names. Twitter allows the one name that you select is your name. I.E. Jim, but you can change the pseudo name often as long as it's not taken i.e. My profile is Jim name ecthed in stone but my pseudo name is "Monster" in Feb and I decide to change it to "flesheater" in March all the while the name Jim sits just below any crazy name I decide to be on any giving day.
Just thinking about it, having a pseudo name will be good for gaming bets. If I loose a bet with someone on my friendlist I would have to change my pseudo name to what they like as long as its not profane.